Chapter U1.17, Problem 1E

Interpretation Introduction

Interpretation:

Evidence provided by flame test that specific atom is present in compounds is to be explained.

Concept introduction:

Different compounds produce different colors in a flame test. Flame test is done by heating a small sample of a compound in a flame such as a Bunsen burner. The color of the flame determines which atom is present in the compound.

Answer to Problem 1E

Each metal atom produces a specific color in the flame test. For example lithium compounds produce red flame, barium produces green flame, sodium produces orange yellow, copper gives blue - green and calcium gives orange colored flame. A pure metal and the compound of the metal both produce same color. By observing the color of flame, one can predict which metal atom is present in the compound. Non - metal atoms do not affect the color of the flame.

Explanation of Solution

Each metal atom is associated with a specific flame color. A flame test can be used to confirm the presence of a particular atom in an unknown sample. If a sodium sample is to be distinguished from a barium sample, it can be easily done by flame test. Sodium compounds burn with orange - yellowish flame while barium compounds burn with green flame.

Color patterns with a flame test also indicate the presence of a specific metal atom in a compound. So if a compound shows blue - green flame; it means copper is present in the compound.

Conclusion

Flame test is an important technique used in scientific laboratories to identify metal atoms in an unknown sample. It is quick and easy to perform.